Many vessels are suited for refilling when the gas or liquid within the tank is depleted. One such example is a propane tank. Fixed maximum liquid level gauges are currently used on propane tanks to assist in refilling of the tank, such as when the tank is refilled with a filling hose. Such gauges are employed to avoid overfilling of the tank. Typically, these liquid level gauges have a tube which extends downwardly into the tank to a predetermined, or to a fixed depth from the top of the tank.
As the propane tank is being refilled, the liquid level within the tank rises until it comes into contact with the bottom end of the tube. When the liquid propane comes into contact with the bottom end of the tube, liquid propane is pushed up into the tube, through an emission limiting bore in the level gauge, and begins to discharge through a bleeder valve in the fixed liquid level gauge. As the liquid propane discharges through the bleeder valve portion of the gauge, a mist or cloud is formed, much like a cloud created by the melting of solid carbon dioxide. This indicates to the person filling the tank, that the tank is now full and that the filling process should be terminated. Thus, the fixed liquid level gauge is also a safety device that assists in preventing the overfilling of the tank.
When the filling of the tank is completed, the bleeder valve portion of the fixed liquid level gauge should be closed or shut off to prevent further discharge and loss of the propane fuel However, this discharge of propane fuel during the filling process also emits propane into the air, thereby tending to increase the amount of pollution in the air Certain jurisdictions are particularly desirous of reducing any pollutants and have laws which limit the amount of pollutants which may be emitted into the atmosphere.
There has therefore been a need for an improved fixed liquid level gauge that substantially reduces the amount of gas, such as propane, that is discharged while refilling the tank.
A general object of the present invention is therefore to provide an improved fixed maximum liquid level gauge which substantially reduces the amount of gas discharged into the atmosphere while refilling of a tank.
Another object of the present invention is to provide an adapter for a fixed maximum liquid level gauge that retrofits existing level gauges to also substantially reduce the amount of gas discharged into the atmosphere
A further object of the present invention is to provide an improved low emission fixed maximum liquid level gauge which is economical to utilize on tanks
Yet another object of the present invention is to provide an adapter or valve for a fixed maximum liquid level gauge which retrofits existing level gauges in an effective and economical manner to substantially reduce emissions.